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<a name="boost_convert.converters_detail"></a><a class="link" href="converters_detail.html" title="Converters in Detail">Converters in Detail</a>
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<dt><span class="section"><a href="converters_detail.html#boost_convert.converters_detail.lexical_cast_converter"><span class="emphasis"><em>boost::cnv::lexical_cast</em></span>
      Converter</a></span></dt>
<dt><span class="section"><a href="converters_detail/stream_converter.html"><span class="emphasis"><em>boost::cnv::stream</em></span>
      Converter</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/stream_converter.html#boost_convert.converters_detail.stream_converter.formatting_support">Formatting
        Support</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/stream_converter.html#boost_convert.converters_detail.stream_converter.formatting_support.numeric_base">Numeric
          Base</a></span></dt>
<dt><span class="section"><a href="converters_detail/stream_converter.html#boost_convert.converters_detail.stream_converter.formatting_support.field_width__fill_character_and_adjustment">Field
          Width, Fill Character and Adjustment</a></span></dt>
<dt><span class="section"><a href="converters_detail/stream_converter.html#boost_convert.converters_detail.stream_converter.formatting_support.leading_whitespace_characters">Leading
          Whitespace Characters</a></span></dt>
<dt><span class="section"><a href="converters_detail/stream_converter.html#boost_convert.converters_detail.stream_converter.formatting_support.format_of_boolean_values">Format
          of Boolean Values</a></span></dt>
</dl></dd>
<dt><span class="section"><a href="converters_detail/stream_converter/locale_support.html">Locale
        Support</a></span></dt>
<dt><span class="section"><a href="converters_detail/stream_converter/supported_string_types.html">Supported
        String Types</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/stream_converter/supported_string_types.html#boost_convert.converters_detail.stream_converter.supported_string_types.wide_string">Wide
          String</a></span></dt>
<dt><span class="section"><a href="converters_detail/stream_converter/supported_string_types/custom_string_types.html">Custom
          String Types</a></span></dt>
</dl></dd>
<dt><span class="section"><a href="converters_detail/stream_converter/the___default_constructible__type_requirement.html">The
        <span class="emphasis"><em>Default Constructible</em></span> Type Requirement</a></span></dt>
</dl></dd>
<dt><span class="section"><a href="converters_detail/strtol_converter.html"><span class="emphasis"><em>boost::cnv::strtol</em></span>
      Converter</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/strtol_converter.html#boost_convert.converters_detail.strtol_converter.basic_deployment">Basic
        Deployment</a></span></dt>
<dt><span class="section"><a href="converters_detail/strtol_converter/formatting_support.html">Formatting
        Support</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/strtol_converter/formatting_support.html#boost_convert.converters_detail.strtol_converter.formatting_support.numeric_base__bin__oct__dec__hex_">Numeric
          Base (bin, oct, dec, hex)</a></span></dt>
<dt><span class="section"><a href="converters_detail/strtol_converter/formatting_support/field_width__fill_character_and_adjustment.html">Field
          Width, Fill Character and Adjustment</a></span></dt>
<dt><span class="section"><a href="converters_detail/strtol_converter/formatting_support/leading_whitespace_characters.html">Leading
          Whitespace Characters</a></span></dt>
<dt><span class="section"><a href="converters_detail/strtol_converter/formatting_support/floating_point_precision.html">Floating-Point
          Precision</a></span></dt>
</dl></dd>
<dt><span class="section"><a href="converters_detail/strtol_converter/supported_string_types.html">Supported
        String Types</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/strtol_converter/supported_string_types.html#boost_convert.converters_detail.strtol_converter.supported_string_types.wide_string">Wide
          String</a></span></dt>
<dt><span class="section"><a href="converters_detail/strtol_converter/supported_string_types/custom_string_types.html">Custom
          String Types</a></span></dt>
</dl></dd>
</dl></dd>
<dt><span class="section"><a href="converters_detail/charconv_converter.html"><span class="emphasis"><em>boost::cnv::charconv</em></span>
      Converter</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/charconv_converter.html#boost_convert.converters_detail.charconv_converter.basic_deployment">Basic
        Deployment</a></span></dt>
<dt><span class="section"><a href="converters_detail/charconv_converter/formatting_support.html">Formatting
        Support</a></span></dt>
<dd><dl>
<dt><span class="section"><a href="converters_detail/charconv_converter/formatting_support.html#boost_convert.converters_detail.charconv_converter.formatting_support.numeric_base__bin__oct__dec__hex_">Numeric
          Base (bin, oct, dec, hex)</a></span></dt>
<dt><span class="section"><a href="converters_detail/charconv_converter/formatting_support/field_width__fill_character_and_adjustment.html">Field
          Width, Fill Character and Adjustment</a></span></dt>
<dt><span class="section"><a href="converters_detail/charconv_converter/formatting_support/leading_whitespace_characters.html">Leading
          Whitespace Characters</a></span></dt>
<dt><span class="section"><a href="converters_detail/charconv_converter/formatting_support/floating_point_precision.html">Floating-Point
          Precision</a></span></dt>
<dt><span class="section"><a href="converters_detail/charconv_converter/formatting_support/floating_point_notation.html">Floating-Point
          Notation</a></span></dt>
</dl></dd>
<dt><span class="section"><a href="converters_detail/charconv_converter/supported_string_types.html">Supported
        String Types</a></span></dt>
<dd><dl><dt><span class="section"><a href="converters_detail/charconv_converter/supported_string_types.html#boost_convert.converters_detail.charconv_converter.supported_string_types.custom_string_types">Custom
          String Types</a></span></dt></dl></dd>
</dl></dd>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_convert.converters_detail.lexical_cast_converter"></a><a class="link" href="converters_detail.html#boost_convert.converters_detail.lexical_cast_converter" title="boost::cnv::lexical_cast Converter"><span class="emphasis"><em>boost::cnv::lexical_cast</em></span>
      Converter</a>
</h3></div></div></div>
<p>
        The purpose of the converter is to
      </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
            Make use of the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code>
            functionality and performance that many people have become accustomed
            to and comfortable with;
          </li>
<li class="listitem">
            Demonstrate how existing independent conversion/transformation-related
            facilities might be incorporated in to the <span class="emphasis"><em>Boost.Convert</em></span>
            framework.
          </li>
</ul></div>
<p>
        The converter can easily replace <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code>,
        adding flexibility and convenience:
      </p>
<p>
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">convert</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">convert</span><span class="special">/</span><span class="identifier">lexical_cast</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">detail</span><span class="special">/</span><span class="identifier">lightweight_test</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>

<span class="keyword">using</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">;</span>
<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">convert</span><span class="special">;</span>
<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span><span class="special">;</span>

<span class="keyword">struct</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">cnv</span><span class="special">::</span><span class="identifier">by_default</span> <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">cnv</span><span class="special">::</span><span class="identifier">lexical_cast</span> <span class="special">{};</span>
</pre>
<p>
      </p>
<p>
</p>
<pre class="programlisting"><span class="keyword">int</span>    <span class="identifier">i1</span> <span class="special">=</span> <span class="identifier">lexical_cast</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;(</span><span class="string">"123"</span><span class="special">);</span>         <span class="comment">// Throws if the conversion fails.</span>
<span class="keyword">int</span>    <span class="identifier">i2</span> <span class="special">=</span> <span class="identifier">convert</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;(</span><span class="string">"123"</span><span class="special">).</span><span class="identifier">value</span><span class="special">();</span>      <span class="comment">// Throws if the conversion fails.</span>
<span class="keyword">int</span>    <span class="identifier">i3</span> <span class="special">=</span> <span class="identifier">convert</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;(</span><span class="string">"uhm"</span><span class="special">).</span><span class="identifier">value_or</span><span class="special">(-</span><span class="number">1</span><span class="special">);</span> <span class="comment">// Returns -1 if the conversion fails.</span>
<span class="identifier">string</span> <span class="identifier">s1</span> <span class="special">=</span> <span class="identifier">lexical_cast</span><span class="special">&lt;</span><span class="identifier">string</span><span class="special">&gt;(</span><span class="number">123</span><span class="special">);</span>
<span class="identifier">string</span> <span class="identifier">s2</span> <span class="special">=</span> <span class="identifier">convert</span><span class="special">&lt;</span><span class="identifier">string</span><span class="special">&gt;(</span><span class="number">123</span><span class="special">).</span><span class="identifier">value</span><span class="special">();</span>

<span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">i1</span> <span class="special">==</span> <span class="number">123</span><span class="special">);</span>
<span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">i2</span> <span class="special">==</span> <span class="number">123</span><span class="special">);</span>
<span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">i3</span> <span class="special">==</span> <span class="special">-</span><span class="number">1</span><span class="special">);</span>
<span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">s1</span> <span class="special">==</span> <span class="string">"123"</span><span class="special">);</span>
<span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">s2</span> <span class="special">==</span> <span class="string">"123"</span><span class="special">);</span>
</pre>
<p>
      </p>
<p>
        See the <code class="computeroutput"><a class="link" href="../boost/cnv/lexical_cast.html" title="Struct lexical_cast">boost::cnv::lexical_cast implementation</a></code>
        for details.
      </p>
<p>
        In order for a user-defined type to be integrated into the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code> framework and, consequently,
        deployed with the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">cnv</span><span class="special">::</span><span class="identifier">lexical_cast</span></code>
        converter:
      </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
            <span class="emphasis"><em>TypeOut</em></span> needs to be <a href="http://en.cppreference.com/w/cpp/named_req/CopyConstructible" target="_top"><span class="emphasis"><em>Copy
            Constructible</em></span></a>;
          </li>
<li class="listitem">
            <span class="emphasis"><em>TypeOut</em></span> needs to be <a href="http://en.cppreference.com/w/cpp/named_req/DefaultConstructible" target="_top"><span class="emphasis"><em>Default
            Constructible</em></span></a>;
          </li>
<li class="listitem">
            <span class="emphasis"><em>TypeOut</em></span> needs to be <span class="emphasis"><em>Input Streamable</em></span>;
          </li>
<li class="listitem">
            <span class="emphasis"><em>TypeIn</em></span> needs to be <span class="emphasis"><em>Output Streamable</em></span>.
          </li>
</ul></div>
<p>
        The first two requirements are imposed by the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code>
        design and implementation and the last two requirements by the underlying
        <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">stringstream</span></code> engine.
      </p>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2009-2022 Vladimir
      Batov<p>
        Distributed under the Boost Software License, Version 1.0. See copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>.
      </p>
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